> ad hoc syntaxes like JIRA's
Gak, yeah, I empathize. JIRA was a pain point for me too.
I take comprehensive notes using org-mode (including all of my false turns, dead ends and "explore this later"s) and when I need to paste something into a ticket I export via ox-jira.el and copy/paste what I need. It works much better than the author's modest README might lead you to believe, and of course it's hackable.